Humidifier control



y 23, 1957 R. W. wEATHEvRsToN ETAL 3,321,196

HUMIDIFIER CONTROL Filed Jan. 28, 1963 2 Sheets-Sheet 2 INVENTORS FIJIC/MAD H4 Wslqmm ra/v 904- S. MARSH/4L1.

ATTORNEY United States Patent 3,321,196 HUMIDIFKER CGN'IRQI.

Richard W. Weatherston and George S. Marsha, St. Paul, Minn, assiguors, by mesne assignments, to Fram Corporation, Providence, RJL, a corporation of Rhode Island Filed Jan. 28, I963, Ser. No. 254,265 1 Ciaim. (Cl. 261-136) This invention relates to an improvement in Humidifier Control and deals panticularly with an apparatus for turning the humidifier olf when a predetermined moisture content is in the air and turning the humidifier on when the humidity in the air falls below a predetermined minimum.

Humidifiers have long been provided for the purpose of increasing the moisture vapor content of the atmosphere. These humidifiers usually include a fan driven by a fan motor. Controls have been provided for these units, the controls usually being mounted at a point remote from the humidifier to measure the humidity of the air at this point and to control the motor circuit to stop and start the motor fan.

Controls of the type previously used are not usually practical for use in combination with portable humidifiers. When the blower motor is in operation, a humidistat control may be placed in the path of incoming air, and a true humidity reading may be obtained and the blower motor may be turned off when there is sufiicient moisture vapor in the air. However, after the blower has been turned off, there is usually residual moisture in the humidifier which gradually evaporates, thereby increasing the humidity within the humidifier cabinet and in the proximity of the cabinet which is far above the moisture content of the air in other parts of the room or area being humidified. As a result, if the humidistat is mounted within the humidifier cabinet or in close proximity thereto, the humidifier blower will remain inoperative long after the moisture vapor in other parts of the room have dropped below a predetermined desired level. Thus the operation of the humidifier is not reliably controlled where the humidistat forms a part of the portable humidifier.

One obvious answer to this problem would be to connect the humidistat to the humidifier by means of an extension cord so that the humidistat could be placed at a distance from the humidifier. The use of such an arrangement is undesirable for several reasons. In the first place, the separate attachment is in itself a nuisance and is one additional attachment connected to the device by an un sightly cord. Of more importance, is the fact that the humidistat must be placed in a position where it is subject to the circulation of air, and usually it is necessary to adjust the control to fit each position, making the structure impractical in most homes. As a result, portable humidifiers have usually not been automatically controlled.

An object of the present invention resides in the provision of a control which is used in conjunction with a humidifier and which may be used within the humidifier cabinet or attached in close proximity thereto. The arrangement is such that the humidistat is located in the path of air entering the cabinet of the humidifier or near the air intake. As a result, the humidistat will properly function to turn off the fan motor when the ambient air includes sufficient moisture vapor. A small heating element is located in the housing of the humidistat which tends to gently heat the air and to dry the air within the housing of the humidistat when the fan motor is not operating. This heating action is slight so that some time is required to drive sufiicient of the moisture in the humidis'tat housing to operate the humidistat to turn on cushioning material the blower motor. As soon as the blower motor is turned on, outside air is blown into the humidistat housing, and if this air contains sufiicient moisture, the fan motor is again turned off. As a result of this arrangement, the control functions at desired intervals to turn the humidifier on and thereby to sample the air in the room. If the air is sufficiently moist, the fan motor turns off after a short period of operation. If the air is not sufiiciently moist, the fan motor will remain in operation until the humidity in the room, as sampled from the incoming air, reaches a predetermined level.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims:

In the drawings forming a part of the specification;

FIGURE 1 is a perspective view of the control removed from the humidifier.

FIGURE 2 is a perspective view of the humidifier showing the general location of the control.

FIGURE 3 is a longitudinal sectional view through the control showing the general arrangement of parts therein.

FIGURE 4 is a cross sectional view through the control, the position of the section being indicated by the line 44 of FIGURE 3.

FIGURE 5 is a cross sectional view through the control, the position of the section being indicated by the line 55 of FIGURE 3.

FIGURE 6 is a vertical sectional view through the humidifier, showing the control in position therein.

FIGURE 7 is a diagrammatic view of the wiring of the control and connections to the fan motor of the humidifier.

T he control which is indicated in general by the letter A (FIGS. 1, 3 and 6) is designed for use in connection with a humidifier which may be of the type illustrated in general by the letter B (FIG. 6). Liquid to be evaporated by the humidifier B may be supplied from any suitable water source, and where the humidifier is of the portable type, the water may be supplied from a reservoir tank (not shown) carried by the humidifier cabinet.

In the particular arrangement illustrated in FIG. 6, the humidifier B is supported within a water pan 10 having a bottom panel 11 and upwardly extending marginal walls 12 connected to the periphery of the bottom panel 11. In the arrangement illustrated, the humidifier includes a generally cylindrical frame 13 made with a series of vertically spaced wire hoops 14 which are supported by a series of angularly spaced upright rods 15. Four of the equally spaced upright rods 15 extend below the level of the others to provide legs 16 and have outwardly turned lower extremities 17 which form supporting feet. Tubes 19 of encircle the feet 17. The remaining vertical rods 15 are provided with outturned lower extremities 20 which support a bottom hoop 21 which is of somewhat larger diameter than the hoops 14. The hoop 21 forms a stop to limit downward movement of a hollow cylindrical sleeve or blanket 22 of urethane foam or similar material having a porous structure which is sufiiciently coarse to permit the flow of air therethrough.

Certain of the angularly spaced upright rods 15 are provided with radially extending inturned arms 23 which terminate in loop shaped ends 24 at points spaced from the axis of the frame 13. A fan motor 25 is provided with a series of angularly spaced mounting bolts 26 which extend through the loops 24 in a manner to support the motor at the top of the frame 13.

Cushioning washers or grommets are provided between the frame and the bolts 26 to cushion the motor support. The mounting bolts 26 also pass through a pair of valve plates 27 and a valve plate reinforcing disk 29, and nuts 30 hold the structure assembled. The valve plates 27 act to spread the stream of downwardly fiowing air into close contact with the porous sleeve 22. A fan 31 is mounted upon the motor shaft 32 of the motor 25 and acts to force air downwardly about the periphery of the motor 25. A cylindrical shroud 33 is connected to the upper extremity of the frame 13, and encircles the motor 25 and fan 31 to confine the flow of air.

A cylindrical sleeve 34 is provided within the upper portion only of the frame 13. The sleeve 34 is supported by a ring 35 which in turn is supported by the inturned upper ends 36 of certain of the vertical rods 15. The sleeve 34 is provided with angularly spaced apertures 37 which may be in the form of louvers, and which are designed to break up the flow of moisture being flung outwardly from the water elevating cone 39 which will be described. Preferably a relatively short outer sleeve 40 of urethane foam encircles the inner blanket 22 outwardly of the openings 37. The outer sleeve 40 has a much finer pore structure than the blanket 22 so that most of the moisture flung outwardly through the apertures 37 is maintained in the inner blanket sleeve 22.

The cone 39 comprises a funnel-shaped structure including a slightly tapered lower end portion 41 at the lower end and a more sharply tapered upper portion 42. An aperture 43 is provided at the lower end of the lower cone portion 41, and the upper portion 42 of the cone 39 is open. The cone is supported by a spider 43 mounted upon the portion 44 of the motor drive shaft which projects downwardly from the motor. The spider 43 is provided with a hub 45 which encircles the shaft portion 44 and is secured for rotation with respect thereto by means of a set screw 46 or other suitable means.

If desired, a trough 47 may underlie a portion of the breaker sleeve 34 and may be connected by an elbow 49 to a drain tube 50. This tube 50 may be used to drain a certain amount of water from the humidifier cabinet in some instances to lower the concentration of impurities from the water circulated, as disclosed in our Patent No. 3,151,- 188, entitled, Porous Blanket Humidifier, issued Sept. 29, 1964. The trough acts to catch excess water thrown on the breaker sleeve by rotation of the cone 39, also as disclosed in this patent.

In operation, when the motor 25 is energized, the cone 7 portion 41 acts to draw liquid upwardly from the pan 10,

lifting the water to the area within portion 42 of the cone by centrifugal force. When the water reaches the top of the cone, it is sprayed outwardly against the breaker sleeve which acts to finely divide the liquid into a spray which is transmitted to the top of the porous blanket 22. The water drains downwardly through the blanket, and is in the path of air blown through the blanket by the fan 31. At least one side of the outer cabinet 51 is open or perforated as indicated at 52 so that the moist air can leave through at least one of the vertical walls of the humidifier. The air being drawn into the outer cabinet 51 may flow through the perforations 53 in the top 54 of the outer cabinet 51.

The humidifier described is for the purpose of illustration, and the use of the control A is not confined to the particular type of humidifier shown and described. In the arrangement illustrated in FIGS. 2 and 6, the control A comprises a housing 56 that is mounted on the front panel 52 of the outer cabinet 51 above the perforations therein, the control being mounted in any desired manner as by the anchoring screws 55.

The control A, as seen best in FIGS. 1, 3, 4, and 5, is mounted within a generally box shaped enclosure 56 which is preferably formed in two parts one of which may be readily removed from the other. The housing 56 includes a base portion including a base panel 57 and integral end walls 59 and 60 extending at right angles thereto, in parallel relation. The base portion also includes relatively short parallel side walls 61 and 62, the center portion 63 of the side wall 61 being of greater height than the remainder of the side wall. The other portion of the housing 56 includes a cover panel 64 and right angularly extending side Walls 65 and 66. These side walls 65 and 66 extend in parallel relation and telescope outwardly of the side walls 61 and 62 of the base portion of the housing.

The side walls 65 and 66 are both perforated as indicated at 67, the perforations extending through the portions of the side walls which are not in overlapping relation with the side walls 62 and 61, 63 of the base section. The side walls 66 and 62 are held in the proper relationship by ears 69 which are struck from the plane of the side wall 66 to engage the side wall 62 as seen in FIG. 4. The side wall 65 is secured to the center portion 63 of the side wall 61 of the base section by a machine screw 70.

A hollow tube 71 projects from the cover panel 64 and communicates with the interior of the control housing 56. As may be noted in FIGURE 6 of the drawings, the tube 71 projects through an opening 72 in the cylindrical shroud 33 and is encircled by a cushioning grommet 73. The purpose of this arrangement is to provide a circulation of air through the housing 56 of the control A when the fan motor is in operation. The fan blade 31 creates a positive pressure within the unit due to the restriction to the flow of air caused by the porous blanket 22. As a result, as soon as the fan starts in operation,

air from the room entering the outer cabinet 51 through perforations 53 in the top 54, is forced through the humidistat housing 56 causing a virtually immediate reaction on the control, as will be described.

The control A, as seen in FIGS. 3, 4, and 5, includes a switch unit 75 enclosed in a generally rectangular blocklike body 76, the projecting terminals of which are enclosed with a U-shaped strip of insulation indicated at 77. A bracket plate 79 overlies the switch 75, and the switch and bracket plate are secured to an inwardly offset portion 80 of the base panel 57 by machine screws 81. The bracket plate 79 supports a right angularly extending plate 82 which extends toward the housing base 57, and a flange 83 is bent at right angles to the edge of the bracket plate 82 and parallel the bracket plate 79. An arm 84 which is of channel-shaped section throughout the major portion of its length is pivotally supported by a pivot pin 85 extending between the bracket plate 79 and the flange 83. One end of the arm 84 is engageable with the slidable plunger 86 which actuates the switch contact arm 87 in the switch unit 75. Thus the switch contact arm 87 may be swung between two fixed contacts 89 and 90 by pivotal movement of the arm 84.

An extension 91 is provided on the bracket plate 79 and a downturned flange 92 is provided on one edge of the extension 91 extending toward the base plate 57 of the housing. An edge 93 of the flange 92 engages in a pair of opposed V-shaped notches 94 in the sides of a channelshaped arm 95 to act as a fulcrum for the arm 95. An ear 96 projecting from the edge 93 of the flange 92 projects through an aperture 97 in the base of the arm 95 to maintain the arm 95 in proper relation to the flange 92. A spring 99 is anchored at one end to a fixed ear 100 struck from the bracket plate extension 91 and is connected at its other end to one end of the arm 95 as indicated at 101. The other end of the arm 95 is provided with a hook-shaped extension 102 over which is looped the center of an expandable and contractible member 103 which changes in length upon variation of moisture content. The ends of the looped expandable and contractible member are connected at 104 to an arm 105 of a bellcrank lever 106 pivotally supported by a pivot pin 107 extending be tween, and supported by, the bracket plate 79 and parallel flange 83. The second arm 109 of the bellcrank lever 106 extends between the sides of the channel-shaped arm 84 at a point outwardly of the switch plunger 86. Thus when the length of the expandable and contractible member 103 shortens, the bellcrank lever 106 will be pivoted in a clockwise direction to force the switch operating plunger 86 inwardly.

The lever 84 comprises merely a locking lever which is capable of either locking the apparatus from operation,

or maintaining the humidifier in operation irrespective of the humidistat. In order to accomplish this result, an externally threaded shaft 110 extends through an internally threaded sleeve 111 supported in place extending through the end wall by a nut 112. A knob or dial 113 is mounted on the shaft to rotate the same. A cam disk 114 is locked to the end of the shaft 110, and is free to oscillate through an angular distance of slightly less than one hundred eighty degrees. The cam disk 114 is provided with an enlarged diameter segment 115 which is engageable with the end portion 117 of the lever 84. When rotated in a counter-clockwise direction from the position illustrated in full lines in FIGURE 5 to the position shown in dotted outline thereof, the arm 84 is pivoted in a clockwise direction (as seen in FIG. 3) thereby swinging the bellcrank lever 106 in a counter-clockwise position and preventing operation of the plunger 86 of the switch unit 75, thereby preventing the expansion and contraction of the member 103 from operating the switch unit 75. When this is done, the expansion and contraction of the member 103 merely flexes the spring 99.

When the cam disk 114 is rotated into the position shown in full lines in FIGURE 5 of the drawings, the lever 84 is swung in a counter-clockwise direction about its pivot center 85, thus forcing the plunger 86 inwardly and causing the flexible contact arm 87 to engage the fixed contact 90. In such a case, the circuit to the fan motor is completed, and the fan motor will remain in operation continuously. When the cam disk 114 is in any intermediate position, the lever arm 84 will be free to pivot in either direction, and the switch plunger 86 will be completely under the control of the expandable and contractible member 103.

A wire spring 120 is anchored to the bottom panel 57 in any suitable manner as indicated at 121, the free extremity 122 of the spring 120 bearing against the cam disk 114. This spring thus frictionally engages the cam disk and tends to hold the disk in a predetermined position. At opposite extremities of the oscillation of the disk 114, the end 122 of the spring arm 120 will engage into a notch such as 123 which tends to lock the disk in one extreme position or the other. In other words there is a definite tendency for the arm 84 to remain locked once the cam 114 has been turned into either extreme position.

As indicated in FIGURE 3 of the drawings, the switch 75 is provided with a bolt 125 which holds the movable contact 87 in place, and which extends through the blocklike body to provide a terminal 126. The fixed terminal 89 is also held in place by a bolt 127 which terminates in the next terminal 129. The fixed terminal 90 is held in place by a third bolt 130 which terminates in an external terminal 131. The various terminals are connected by suitable conductors to other parts of the circuit.

The wiring diagram is shown in FIGURE 7. This figure diagrammatically shows the lever arm 95 urged in one direction by the spring 99 and drawn in the opposite direction by the expandable and contractible member 103. The member 103 is shown anchored to the bellcrank lever 106 which is pivoted at 107 and which acts to bear against the switch plunger 86. When the member 103 contracts, the bellcrank 106 is pivoted in a clockwise direction as shown in FIGURE 7 urging the flexible contact 87 against the fixed contact 90 and closing a circuit from line wire L-l to the flexible contact blade 87, through the fixed contact 90 and the conductor 132 to one terminal of the motor 25, the other terminal of which is connected to line wire L2. When the member 103 expands in length, the bellcrank lever 106 is free to pivot in a counter-clockwise direction, relaxing pressure on the flexible contact 87. As a result, the flexible contact 87 may flex into engagement with the fixed contact .89 closing a circuit from the line wire L-1 through the flexible contact 87, fixed contact 89, conductor 133, heating element 134 and conductor 135 to the line wire L-Z. The heating element 134 is located within the control housing 56 adjoining the expansible and contractible member 103, and the heat generated by the heating element has a tendency to heat the air and evaporate the moisture in the air within the housing 56.

As the housing 56 is located within the outer cabinet 51 of the humidifier, and as the blanket 22 remains moist after the humidifier fanis turned off, the ambient air within the housing would normally be considerably more moist than the air externally of the cabinet or in other parts of the room in which the humidifier is located. However, the gentle heat from the heating element has a tendency to dry the air within the control housing. Accordingly, instead of having and arrangement in which the motor remains turned 011? long after the humidity of the room air drops below a predetermined level, the control has a tendency to dry the air in the housing 56 at a relatively high rate of speed so that at .rather frequent intervals, the expansible and contractible member 103 will operate the switch 75 to turn on the fan motor 25. As soon as the fan motor 25 is turned on, pressure builds up within the area confined by the shroud 33, causing air to flow through the passage 71 and to circulate the housing 56. It will be noted that the air which is forced into the housing 56 has been drawn from the room, and the circulation of this air through the control housing causes the expansible and contractible member 103 to provide a true indication of the humidity within the room. If the humidity is at a predetermined level, the switch will again be turned off and will remain off until the heating element within the housing 56 dries out the air within the housing sufficiently to cause the motor circuit to once again be closed. If, on the other hand, the room air is found to contain less than the desired amount of moisture, the fan motor will continue to function until the air entering the outer cabinet and circulated through the housing 56 contains sufiicient moisture to again operate the switch 75 to open the motor circuit and to again close the circuit to the heating element. Conversely, while the motor circuit is closed through switch 75 and the fan is operating, the circuit to the heating element will be open.

It will be noted that in this way, the control functions to sample the room air at desired intervals and to either turn off the fan motor after a short period of operation, or else allow it to continue to operate until the air contains the proper amount of moisture.

At times when no operation of the humidifier is desired, the knob 113 may be rotated to lock the lever arm 84 in position to hold the bellcrank lever 106 from pivotal movement, therefore preventing the operation of the humidifier by preventing operation of the motor. If, on the other hand, it is desired to operate the humidifier continuously, this may be accomplished by locking the arm 84 in its other extreme position in which the flexible contact 87 is held in engagement with the fixed contact 90, and the motor circuit is continuously energized regardless of expansion or contraction of the moisture sensing member 103.

In accordance with the patent statutes, we have described the principles of construction and operation of our improvement in humidifier control, and while we have endeavored to set forth the best embodiment thereof, we desire to have it understood that changes may be made within the scope of the following claims without departing from the spirit of our invention.

We claim:

In combination with a humidifier having an inner enclosure with an air inlet thereto and an air outlet therefrom remote from said inlet, an electric motor carried by said enclosure, a fan driven by said motor for drawing air into said inlet, into said enclosure and toward said outlet, a porous blanket adjoining said outlet and through which air must pass from said inner enclosure and from said outlet, means for supplying water to said blanket, and an outer cabinet enclosing and surrounding said inner enclosure in spaced relation thereto, said cabinet having an inlet and an outlet communicating with the said inlet and outlet of the said inner enclosure, a control for the humidifier including,

a humidistat enclosed within a perforated housing, an expansible and contractible element in said humid-istat housing, responsive to variations in humidity, switching means in said housing operable in one conditionof said element to energize said electric motor and drive said fan when the moisture content of air adjacent said element falls to a predetermined minimum, said switching means being operable in a second condition of said element to de-energize said motor and stop said fan when the moisture content of the adjacent air rises to a predetermined maximum, means supporting said humidistat housing in said outer cabinet in the space between said cabinet and inner enclosure and adjacent said inlets of said cabinet and of said inner enclosure, means providing an air passage between said humidistat housing and said inner enclosure adjacent its air inlet, whereby when said fan is in operation air will be forced from said cabinet inlet through said humidista-t housing, and

an electrical heater supported in said humidistat housing adjacent to said humidity-responsive expansible and contractible element, energized to evaporate moisture in the air adjacent to said humidity-responsive element when said switching means is operated in its said second condition to de-energize said motor and stop said fan.

References Cited by the Examiner UNITED STATES PATENTS 1,727,099 9/ 1929 Cochrane 236-44 2,094,342 9/ 1937 Bichowsky 62-94 X 2,595,673 5/1952 Grosvenor et al. 23644 2,730,340 1/1956 Patriarca 26172 X 3,193,261 7/1965 Nesbitt 261-142 3,206,118 9/1965 Champel 23644 HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner.

E. H. RENNER, Assistant Examiner. 

